In the field of hoisting devices to be used for hoisting and mounting building elements; especially glazing panels, it is common practice to use a telehandler equipped with a vacuum gripper rack to grip and hoist a panel to be mounted in a wall or vehicle body and then fit it into its final position.
There are custom-built glass lifters available for short-range operations and for long-range operations, and for a number of reasons there also exists glass hoisting attachments to be suspended from a crane outrigger or to be mounted on a front end loader replacing e.g. a forklift attachment or bucket attachment.
Already in the 1960's a de facto standard for mounting means on many loaders was established by the Bobcat Company with their Bob-Tach® system (U.S. Pat. No. 3,672,521 Bauer et al.). The industry developed attachments or implements cooperating with said standardized system, thereby opening a door to a huge market of existing and future loaders ready to accept the standardized implements.
The actual problem dealt with in this invention is that the machinery used to hoist heavy glazing panels often is not able to bring the panels all the way into the waiting openings without an operator having to manually maneuver heavy panels the last distance. Such hard work would often be challenged by occupational health regulations.
US patent application no. 2007/0189882 A1 (Smith et al.) describes an attachment for a telescopic material handler for manipulating a load. The attachment includes a gripping system and a manipulation assembly.
An essential task to be solved, when heavy glazing panels are hoisted to a site at a high level above ground, is that the delicate maneuvering of the gripper rack carrying a panel during the final stages of positioning and mounting said panel requires a higher precision and control of movements than offered by a gripper assembly operated by a fully extended crane or boom, and consequently an adjustment head to be used with any standard hoist device but functionally independent therefrom and having a high degree of precision control of the gripping rack is the aim of the invention.
The said US application does provide many degrees of freedom, but a missing vital degree is to extend the reach of the implement, after a correct alignment is secured. Moreover, it is important that the implement is self-contained and only needs power from an external source to be a separate fully functional implement and not relying on external hydraulic sources.
A further disadvantage with said US application is that some incremental adjustments result in too large movements.
Accordingly, it has been important to consider a solution wherein at least some of the incremental adjustments result in shorter distances moved. An advantageous way of obtaining this comes from arranging the pivot points as close as possible to the panels to be mounted.